Objectives: FOX-type enzymes are a lineage of AmpC-type β-lactamases from Aeromonas spp. whose genes have been mobilized to plasmids spreading among Enterobacteriaceae, where they can be responsible for resistance to extended-spectrum cephalosporins and β-lactamase inhibitor combinations. Little is known about the genetic context and plasmid vehicles of blaFOX determinants. Here,we have characterized a plasmid encoding the FOX-7 β-lactamase, which was involved in a large outbreak caused by two Klebsiella pneumoniae clones in a neonatal intensive care unit. Methods: Plasmid transferability was tested in conjugation experiments using Escherichia coli recipients. Plasmids from different strains were compared by restriction profiling and PCR mapping. The complete sequence of pFOX-7a plasmid was determined by a next-generation sequencing approach followed by gap filling using PCR and sequencing. Results: An apparently identical conjugative plasmid encoding FOX-7 was detected in representatives of the K. pneumoniae clones that caused the outbreak and in sporadic FOX-7-producing strains of other species from the same ward. The plasmid, named pFOX-7a, has an IncL/M-type backbone and two separate resistance modules including a Tn3-like transposon and a novel Tn1696 derivative, named Tn6234, which carries an integron platform, a hybrid (but still functional) mercury resistance module and a novel putative transposon of original structure, named Tn6240, associated with the blaFOX-7 gene. Conclusions: pFOX-7a is the first completely characterized plasmid encoding a FOX-type β-lactamase. The blaFOX-7 gene was associated with a putative transposable element of original structure, which was likely involved in its mobilization from the Aeromonas metagenome.

Di Pilato, V., Arena, F., Giani, T., Conte, V., Cresti, S., Rossolini, G.M. (2014). Characterization of pFOX-7a, a conjugative IncL/M plasmid encoding the FOX-7 AmpC-type β-lactamase, involved in a large outbreak in a neonatal intensive care unit. JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, 69(10), 2620-2624 [10.1093/jac/dku216].

Characterization of pFOX-7a, a conjugative IncL/M plasmid encoding the FOX-7 AmpC-type β-lactamase, involved in a large outbreak in a neonatal intensive care unit

Di Pilato, V.;Arena, F.;Giani, T.;Conte, V.;Rossolini, G. M.
2014-01-01

Abstract

Objectives: FOX-type enzymes are a lineage of AmpC-type β-lactamases from Aeromonas spp. whose genes have been mobilized to plasmids spreading among Enterobacteriaceae, where they can be responsible for resistance to extended-spectrum cephalosporins and β-lactamase inhibitor combinations. Little is known about the genetic context and plasmid vehicles of blaFOX determinants. Here,we have characterized a plasmid encoding the FOX-7 β-lactamase, which was involved in a large outbreak caused by two Klebsiella pneumoniae clones in a neonatal intensive care unit. Methods: Plasmid transferability was tested in conjugation experiments using Escherichia coli recipients. Plasmids from different strains were compared by restriction profiling and PCR mapping. The complete sequence of pFOX-7a plasmid was determined by a next-generation sequencing approach followed by gap filling using PCR and sequencing. Results: An apparently identical conjugative plasmid encoding FOX-7 was detected in representatives of the K. pneumoniae clones that caused the outbreak and in sporadic FOX-7-producing strains of other species from the same ward. The plasmid, named pFOX-7a, has an IncL/M-type backbone and two separate resistance modules including a Tn3-like transposon and a novel Tn1696 derivative, named Tn6234, which carries an integron platform, a hybrid (but still functional) mercury resistance module and a novel putative transposon of original structure, named Tn6240, associated with the blaFOX-7 gene. Conclusions: pFOX-7a is the first completely characterized plasmid encoding a FOX-type β-lactamase. The blaFOX-7 gene was associated with a putative transposable element of original structure, which was likely involved in its mobilization from the Aeromonas metagenome.
2014
Di Pilato, V., Arena, F., Giani, T., Conte, V., Cresti, S., Rossolini, G.M. (2014). Characterization of pFOX-7a, a conjugative IncL/M plasmid encoding the FOX-7 AmpC-type β-lactamase, involved in a large outbreak in a neonatal intensive care unit. JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, 69(10), 2620-2624 [10.1093/jac/dku216].
File in questo prodotto:
File Dimensione Formato  
Characterization-of-pFOX-7a-2014.pdf

non disponibili

Descrizione: Articolo
Tipologia: PDF editoriale
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 707.72 kB
Formato Adobe PDF
707.72 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/48825
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo